In earlier studies conducted by the applicants, the "Estimated Survival Probability" (ESP) index was developed and proposed as a technique for grading the severity of hospitalized trauma on the basis of ICDA codes. This index was developed using data from the 1973 Hospital Discharge Survey (HDS). In this proposed study, data from three insight into the nature and strength of the associations between outcome of hospitalized trauma and such variables as age, sex, bed size of hospital, number of conditions mentioned (both trauma and non-trauma), number and type of surgical codes and other factors, with length of stay and discharge status (alive or dead) used as outcome variables. Modern methods of contingency table analysis will be used to test the appropriate hypotheses concerning these associations. It is felt that the improved ESP index will be a useful tool to investigators involved in retrospective studies of hospitalized trauma, and that the insight gained from this study into factors associated with outcome of trauma can be used in the planning of emergency medical services.